Multi-caliber conversion kits for semi-automatic pistols

ABSTRACT

A multi-caliber modular center fire line of conversion kits adaptable to pistols such as the Colt Government Model Pistol or new semi-automatic handguns. Said kits consist of complete slide assemblies using interchangeable components adapted to different sizes of ammunition. All barrels in the kits have external dimensions identical to those of the largest caliber one in order to have the primer of a loaded cartridge, whatever its caliber, automatically centered in front of the firing pin hole on the breech inside a locked pistol. When installed on semi-automatic pistol frames, kits function exactly like the original handgun.

BACKGROUND OF THE INVENTION

This invention relates to modular multi-caliber conversion kits usinginterchangeable center fire barrels of different calibers and lengths inslides adaptable to Colt Government Model Pistol (aka M 1911 .45 caliberor simply “1911”), its copies and variants and new pistols.

The 1911, which evolved from several earlier John Moses Browningpatents, is a short-recoil locked-breech pistol: at the start of thefiring cycle, slide and barrel are interlocked by two lugs on top of thebarrel into corresponding grooves inside the roof of the slide. As ashot is fired, barrel and slide recoil together for a short distanceuntil the rear end of the barrel is forced down by its pivoting link andstopped. The downward movement of the barrel disengages it from theslide which continues rearward compressing the recoil spring, extractingthe spent case from the chamber, ejecting it and cocking the hammer.After the slide reaches the limit of its rearward travel, the recoilspring pulls it forward stripping the top cartridge from the magazineand feeding it into the chamber. At this point, the pivoting link movesupward the rear end of the barrel which twin lugs engage the groovesinside the slide locking the breech, the slide achieves its forwardmovement and the pistol is ready to fire again.

On the early Thirties, John Moses Browning patented for the Belgian HighPower 9 mm pistol an improved version of this principle. The operatingcycle of the High Power remains similar to that of the 1911 but itsslide has no removable barrel bushing and the rear end of the barrel isnot moved vertically by a pivoting link but instead a slot in anintegral extension at its rearmost part which contacts a hardened crossbar inside the frame. After the short rearward movement of the slide andbarrel assembly, the slot engages the bar, the rear end of the barrel isdrawn downward by the camming action of these two parts and stoppedwhile the slide continues to recoil in order to complete the operatingcycle.

The French 1935S pistol was still using a pivoting link barrel but itoffered another improvement: instead of two lugs fitting oncorresponding recesses, its barrel has on top of the chamber an integralsharp shoulder which engages a cut inside the slide. The combination ofthe High Power and the 1935S locking methods is currently in use on allmodern pistols working on the tilting barrel locking principle.

Franz-Joseph Peters U.S. Pat. No. 4,920,676 for an interchangeablebarrel pistol uses a special slide having a spring loaded claw oppositeto the extractor to support different size cartridge bases on the samebreech face. On his further U.S. Pat. No. 5,133,142, , the same inventorstates about his previous one: “In this known solution, however, theproduction and assembly of the resilient holding claw involve arelatively high outlay. The contour of this holding claw and the elasticpressing force of the holding claw have to be carefully coordinated, soas to guarantee that the pull-out system functions perfectly”, and hereplaces the additional claw of U.S. Pat. No. 4,920,676 by an adapterpiece which has to be manually adjusted on the slide according to thedimensions of the new cartridge base.

The present invention represent a considerable improvement over the twoabove ones as it needs less components of a simpler design, andswitching of barrels requires no previous manipulation of an adapter.

BRIEF SUMMARY OF THE INVENTION

This invention is based on the observation that in a semi-automatichandgun using the Colt-Browning tilting barrel locking principle exposedabove, different barrels having the same external dimensionscorresponding exactly to the internal dimensions of a pistol slide willautomatically remain in the same position inside the locked handgun. Asa result, in any of such barrels having a correctly centered bore, theprimer of a loaded cartridge, regardless of its caliber, will always beexactly in front of the firing pin hole on the breech face of the slidewhen the pistol is ready to fire. This particularity makes possibleproduction of conversion kits having interchangeable barrels ofdifferent calibers which can be directly installed in alternance on thesame slide. Conversion kits built on this principle can replace theslide assembly of all pistols working on the Colt-Browning principle,from the century old Colt Government Model Pistol to single or doubleaction modern semi-automatic handguns or being used to build totally newones.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a right side view of a pivoting link short feed ramp barrelwith its bushing;

FIG. 2 is a right side view of a pivoting link extended feed ramp barrelwith its bushing;

FIG. 3 is a right side view of a linkless short feed ramp barrel of thesecond model conversion kits with its bushing;

FIG. 4 is a right side view of the linkless extended feed ramp barrel ofthe second model conversion kit with its bushing;

FIG. 5 is a right side view of the locking block used on second andthird models conversion kits showing in a the inclined top lug and in bthe integral long recoil spring guide;

FIG. 6 is a simplified right side view of an exploded 1911 type pistolframe showing in c the longitudinal milling cut required to install onsuch a frame conversion kits using linkless extended feed ramp barrels;

FIG. 7 is a right side view of the new design square chamber short feedramp of the third model conversion kits, used indifferently in new modelslides with or without barrel bushings;

FIG. 8 is a right side view of the new design square chamber extendedfeed ramp linkless barrel of the third model conversion kits usedindifferently in new model slides with or without barrel bushings butrequiring the FIG. 6 c milling cut on the pistol frame or a new frameoriginally built as such;

FIG. 9 is an exploded left side view of the new design slide with barrelbushing showing the integral top extension of a square chamber shortfeed ramp barrel interlocked in the open top of the remodeled ejectionport;

FIG. 10 is an exploded left side view of the new design bushinglessslide showing the integral top extension of a square chamber extendedfeed ramp barrel interlocked in the open top of the ejection port.

DETAILED DESCRIPTION OF THE INVENTION

Multi-caliber conversion kits for 1911 type pistols usinginterchangeable barrels of different lengths and models in slides havinginternal dimensions corresponding exactly to the external dimensions ofsaid barrels. These kits include all necessary interchangeable parts andaccessories making possible a fast change of caliber on the samehandgun. They are designed in three models, the two first ones using acommon slide with main specifications identical to those of the original.45 caliber Colt Government Model Pistol except for an external groovenecessary to install the interchangeable extractors adapted to therequired caliber.

The first models use pivoting link barrels of the original short feedramp design (FIG. 1) which install directly on regular pistol frames orextended feed ramp ones (FIG. 2) of a type already in current use whichrequire frames modified by milling cuts in front of the magazine well.

The second models use improved linkless barrels of the short feed rampdesign (FIG. 3) having integral underside ramps which engage theinclined lug (FIG. 5 a) of a removable locking block or extended feedramp linkless barrels (FIG. 4) using the same type of locking blockeither on pistol frames modified as on FIG. 6 c or on new framesoriginally designed as such.

The third model kits have slides of a new design and linkless barrelsbuilt with underside ramps identical to those of the second model onesin order to also use the same type of locking blocks: the short feedramp barrels will fit regular frames, the extended feed ramp ones eitherframes modified as on FIG. 6 c or new ones originally designed as such.Slides are made with removable barrel bushings (FIG. 9) to permitinstallation of heavy bull barrels and readily available customaccessories and as simplified bushingless models (FIG. 10). New modelsquare chamber barrels (FIG. 7) and (FIG. 8) are installed from thebottom of the slides and interlock the modern way in top of the enlargedejection ports by integral extensions over their squared chambers (FIGS.9) and (10) instead of the original grooves used on the two first modelsof kits.

All kits are of simple and proven design without additional small partsand several of their components are made to fit the different models inorder to reduce production costs. The removable locking blocks (FIG. 5)used with the linkless barrels in the second and third model kits aremachined or cast in hardened steel or any other suitable strong materialto fit exactly inside the original barrel link assembly housing of a1911 type frame where they are securely held by the slide stop crosspin. While short recoil spring guides or captive spring removable unitswould also work on these locking blocks, integral long recoil springguides which front end slip inside the drilled recoil spring plugs (orthe apertures in front of the bushingless slides) have the advantage ofpractically eliminating any possible play of the moving parts in alocked pistol, improving the potential accuracy of the handgun.

1-3. (canceled)
 4. A multi-caliber line of modular center fireconversion kit using interchangeable barrels of different calibers andlengths in a same type of slide assembly made to fit Colt GovernmentModel Pistol frames, their copies, variants or new pistols, comprising:(A) slides as set forth on claim 4 using interchangeable externalextractors but having otherwise internal specifications identical tothose of a standard .45 Colt Government Model Pistol slide; (B)interchangeable barrels of different calibers (FIG. 1) having otherwiseexternal specifications identical to those of standard .45 ColtGovernment Model Pistol barrels in order to fit slides as set forth onclaim (A); or (C) interchangeable barrels of different calibers withextended feed ramp of a type already in production (FIG. 2) havingotherwise specifications as set forth on claim (B) but whichinstallation on standard Colt Government Model Pistol type framesrequire either a longitudinal cut milled in top front part of themagazine well of said frames (FIG. 6 c) or new frames originally madewith such modification; (D) barrel bushings, recoil spring guides andrecoil spring plugs of a type usable on standard Colt Government ModelPistol slides, recoil springs, extractors, ejectors and magazinesadapted to the type of ammunition used in the kit; (E) interchangeableshort feed ramp linkless barrels of different calibers with the usualpivoting link assembly replaced by integral underside locking ramps(FIG. 3) but having otherwise external specifications as set forth onclaim (B); or (F) interchangeable linkless barrels as set forth on claim(E) except for having an extended feed ramps and locking ramps (FIG. 4)of a different design which installation on Colt Government Model Pistoltype frames require either a longitudinal cut milled in top front partof the magazine well of said frames (FIG. 6 c) or new frames originallymade with such modification; (G) removable locking blocks (FIG. 5)having integral recoil spring guides a and inclined top lugs bwhichengage the corresponding locking ramps of linkless barrels as set forthon claims (E) and (F); (H) barrel bushings as set forth on claim (D) anddrilled recoil spring plugs of a type usable on standard Colt GovernmentModel Pistol slides, recoil springs, extractors, ejectors and magazinesadapted to the type of ammunition used in the kit; or (I) slides as setforth on claim 4 but having enlarged ejection ports instead of the usualColt Government Model Pistol type twin internal locking grooves, flatinternal sides from the breech to half an inch of the internal front endin order to use standard barrel bushings as set forth on claim (D),drilled recoil spring plugs as set forth on claim (H) and squaredchamber barrels as set forth on claim (J) installed from the bottom ofthe slide (FIG. 9); (J) interchangeable linkless short feed ramp barrelsof different calibers and lengths (FIG. 7) having on top of theirsquared chambers integral extensions which interlock in the enlargedejection port of slides as set forth on claim (I), and designed to have,regardless of their calibers, external specification corresponding tothe internal specification of said slides; (K) barrel bushings as setforth on claim (D), drilled recoil spring plugs as set forth on claim(H), removable locking block as set forth on claim (G), recoil springs,extractors, ejectors and magazine adapted to the type of ammunition usedin the kit;. or (L) slides as set forth on claim (I) but having longerflat internal sides going from the breech to the internal front end ofsaid slide, and circular apertures for barrel and recoil spring guideson their integral muzzle ends (FIG. 10) thus requiring no barrelbushings and recoil spring plugs; (M) interchangeable linkless barrelsas set forth on claim (J) except for having an extended feed ramp andlocking ramps of a different design (FIG. 8) which installation on ColtGovernment Model Pistol type frames require either a longitudinal cutmilled in top front part of said frames magazine well (FIG. 6 c) or newframes originally made with such modification; (N) removable lockingblock as set forth on claim (G), extractors, ejectors and magazineadapted to the type of ammunition used in the kit.